Drying apparatus.



C. H. CURRI'ER.

DRYING APPARATUS, APPLICATION FILED SEPT. 15, 1916.

2 SHEETS-SHEET 2.

w n HH l lnl HNNW H k @%w NM Q CHARLES H. CURBIER; OF NEWARK, NEWJERSEY.

DRYING APPARATUS.

To all whom z'tmay concern:

Be it known that I, CHARLEs H. CU'RBIER, a citizen of the United States,residing at Newark, in the county of Essex and State of New Jersey, haveinvented certain new and useful Improvements in Drying Apparatus, ofwhich the following is a specification.

My invention relates broadly to dryingovens or kilns, which are widelyused for drying coats of varnish, stain or filler on.

. wood and metal, and for similar purposes,

' gree of moisture or humidity. It is also useand also relates toimprovements in apparatus designed to supply such ovens or kilns withdustless air which is of the proper tem perature andwhich contains theproper deful for drying gluedveneers and stock.

For drying purposes and particularly in connection with oods which arecoated with varnish, it is deslrable .and ractically essential toproduce what may e called a perfeet drying day, in other words, airconditions which are proper both from the standpoint of the temperatureof the air and of its humidity, as well as its freedom from dust. Thedrying of varnish, for instance, requires heat, moisture and a largesupply of oxygen, since the operation is not purely a drying action, butinvolves also a chemical oxidation of certain of the ingredients of thevarnish.

Consequently perfect drying-of the coat can-- not be obtained unless theoperation is carried on in a current of air' which is warm enough toralse the temperature of the varnish so as to accelerate the rate ofevaporation of certain of its volatile content, and which is moistenough to prevent the varnish from case-hardening or surface-drying,since thevarnish should properly dry from the i '40 base outwardly tothe surface. Furthermore,

there must be sufiicient oxygen supplied to oxidize the linseed oil andto react on certain of the other components of the varnish. It

, is also desirable that the current of air thus supplied not only havethe characteristics just described, but also be freefrom dust whichotherwise would'mar the finish of the varnish. Y

- In order to accomplish the perfect drying of such articles as have.been specified, it iscustomary to place them in specially constructedrooms, ovens or kilns-1n which the conditions of air supply may. beaccurately controlled. At the same time, it is. necessary thatconditions throughout the kiln be as uniform as possible in order toprevent air Specification of Letters latent. I Patented J 1111 19 1917,Application filed September 15, me. Serial No. 120,225. Y i

in one stratum having substantially different I properties from that 1nanother stratum. My invention consequently relates both to the design'ofthe kiln for attaining as nearly uniform conditions therein as maybeffeasi- 'ble and also the construction and arrangement of theapparatus associated 'with the kiln for'supplyingito it the conditionedair to approximate the perfect drying day.

In the accompanying drawings, which form a part of this specification,"Figure *1 is a plan view of one'type of kiln'and its v associatedapparatus. constructed in accord--- ance with my invention. Fig. 2 is atrans-- verse sectional view through the kiln. Fig;

3 is a view similar to Fig. 2 showing a slightly modified form ofconstructiom Fig. 4 is a plan viewon an enlarged scale'ofthe apparatusshown at the left of- Fig. '1', which suppliesthe air to the kiln. Fig.'5 is'a side i elevation of the device of Fig. 4,.and Fig. 6 is alongitudinal sectional view through a kiln having the modified form ofduct 0on This isto provide ample airsupply for a plurality of verticaldownwardly extending supply ducts 6 which terminate. at their lower.ends in openings 7, which are controlled by dampers 8. Along theceilingat the opposite side of the room extends an outlet or vent duct9, which is providedwith downwardly. extending'vent ducts 10, which I iare, similar to the ducts 6 and whose open.

ends 11 may be controlled by the'da mpers12. The outlet duct 9 islikewise graduated. or

stepped in size asshown in Fig. 1,.the p art 7 of largest dimensionbeing near the center of v the kiln and 'adjacentto the vent pipe 13,105.

which leads to the outer atmosphere.

I have found thatin order to obtain eflicient drying, it is highlydesirable that a system of cross-ventilation beset up, such as that.produced by the construction shown in no Figs. 1 and 2, in which thesupply or inlet ducts and the vent ducts are substantially similarlyarranged transversely of the kiln.

This prevents any dead spaces and also insures a pure cross-ventilationwithout eddy currents which might act to prevent the uniform circulationof the heated air through the kiln. I also prefer to use a system inwhich the air enters under a slight pressure, for example, 600 feet perminute velocity, since it will then of its own accord displace the airalready in the kiln and force it out of the vent ducts, at the same timepreventing any outside air from entering the kiln through any accidentalopening therein and thus overcoming the possibility of dust beingbrought into the kiln.

In Fig. 3, I have shown a modified form of construction in which themain supply duct 14: lies along one side of the kiln near the floor andis provided with a plurality of spaced apertures 15 opening toward thefloor. Each of these apertures may be controlled by a suitable damper16. I may also use a vent duct of somewhat similar construction in whichthe orifice 17 is adjacent to the floor, the duct 18 leading outwardfromthe kiln and being controlled by a damper 19. Both ducts will, ofcourse, be suitably graduated in size as before.

It will be appreciated that while theoretically, it may be desirable toposition the inlet and outlet ducts in pairs directl opposite eachother, this is in practice oftenimpossible owing to the occurrence ofdoors, columns, or other obstructions, and in fact, is not essential solong as an approximately symmetrical arrangement isprovided without deadspaces.

Figs. 4 and 5 illustrate on an enlarged scale the device which I preferto use for supplying the air approximating the conditions of a perfectdrying day. In the apparatus 20 is the fresh air intake through whichatmospheric air gs drawn in by suction. The air first passes through theair washer and humidifier. 21. In this journey the air travels through amist or spray formed by water forced through the nozzles 22. Thesenozzles are connected to a supply pipe 23, which is fed from anysuitable source, as the centrifugal pump 24, which may be driven bymeans of the electric motor 25 through the belt 26. This pump preferablyhas its intake 27 connected-through a strainer 28 to a water well 29,which forms the bottom of the air washer and humidifier well iscontrolled by means of suitable heaters 29 fed from the steam pipe 30.After the air passes through the spray or mist in the washer andhumidifier, it continues through the eliminators 31, which are merelyangularly-disposed baffle plates, and then ,passes through the heatingchamber 33,

where it may be heated to any desired de- 'gree by means of steamheaters supplied from the main 34, the steam leaving the The temperatureof the water in this heaters through the return pipe 35. From the heaterthe air is drawn by suction into the intake 36 of a centrifugal fan 37,which may be driven in any suitable manner, as by being belted to theelectric motor 38. This fan delivers the air under pressure through itsoutlet 39 into the main inlet or supply duct 3 already described.

As has been above pointed out, it is necessary to control threecharacteristics of the air; first, the dust content; second, itshumidity or moisture content; and third, its temperature. All of theseconditions are governed by the apparatus shown in Figs. at and 5. Thedust is readily eliminated by the passage of the air through the mist orspray fromthe nozzles 22, this intermingling of the air with the spraymechanically washing the air, and all dust or dirt held in suspension inthe air falling to the bottom of the tank 29. The process of governingthe humidity of the air about to enter the kiln is somewhat morecomplicated and is accomplished by first bringing the air toa knownpoint of humidity and then heating it to the required temperature. Themost easily attained starting point is that of practically completesaturation; that is a condition of 100 per cent. humidity, and as theair passes through the mist or spray emanating from the nozzles 22, itautomatically takes up sufficient moisture to saturate it completely atthe temperature of the water forming the mist or spray. This temperatureis easily controlled by governing the amount of steam admitted to thepipe 30 through the dia phragm valve 40, which in turn is controlled bya thermostatic device 41, preferably situated just back of theeliminators. The particular construction of the diaphragm valve and itsthermostatic control forms no part of my present invention, since suchvalves and controlling means are well known in the art, and they willnot be described here in detail. It is simply necessary to set the thermostatic control 41 at the desired temperature. This control then actson the diaphragm valve 40 either to admit steam to the pipe 30 or toshut it off, as the case may be, in order to maintain the desiredtemperature of the air passing through the eliminators and striking thecontrol. By this means, I produce a current of air passing through theeliminators which is in a condition of nearly complete saturation or 100per cent. humidity at the temperature for which the thermostat 4:1 isset. The only function of the eliminators is to take from the air anyparticles of moisture which may be carried along in the form of mist andnot as true water vapor. As the air passes through the eventually dripsinto the tank 29. The loss of water from the tank 29 due to the moisturetaken up by the air is made good from time to time from any suitableoutside supply.

Now, if the air upon passing through the ballle plates is completelysaturated with moisture and is, for example, at a temperature of 87, itwill contain 13.12 grains of water vapor per cubic foot. Suppose the airin the kiln is desired to be at a temperature of 112 with a relativehumidity of 47 per cent; this humidity at a 112 temperature represents13.12 grains of water vapor per cubic foot, and consequently it is onlynecessary to supply sufficient steam through the main 31 to the heaters33 to raise the temperature of the air to 112,

since it already contains the 13.12 grains of water vapor per cubic footrequired to give the 17 per cent. humidity at 112. In other words,merely by adjusting the temperature of the water sprayed through thenozzles 22, so as to obtain saturated air containing the desired numberof grains of water vapor, and then subsequently raising the temperatureof this saturated air in the heater 33, I may obtain any desiredtemperature of the air entering the kiln and likewise any desiredhumidity. The inlet of steam to the main 3t and consequently the heater33 is.

controlled by a diaphragm valve 42, which may be similar in itsconstruction to the valve 40 and this valve is in turn governed by athermostatic control 43 preferably located on the exhaust or vent sideof the kiln. It will be appreciated that in the example given above, forinstance, the air passing through the heater 33 will actually be raisedto a temperature much greater than 112, say 152, in order to compensatefor radiation losses in the ducts and kiln.

\Vhile I have illustrated and described only certain preferredembodiments of my invention, I realize that it is susceptible of wideadaptation and I do not desire to be limitedto the precise constructionshown and described.

lIaving thus described my invention, I claim:

1. In apparatus of the class described, a kiln, inlet and outlet airducts therefor located on opposite sides thereof, both sets of ductsopening downwardly toward the floor of the kiln, and means for supplyingconditioned air under pressure to the inlet ducts.

2. In apparatus of the class described, a kiln and inlet and outlet airducts therefor located on opposite sides thereof and arrangedtransversely of the kiln, said ducts pplening downwardly toward thefloor of the 3. In apparatus of the class described, a kiln, inlet andoutlet air ducts therefor located on opposite sides thereof, said ductsopening downwardly toward the floor of the kiln and within a shortdistance the eof, and means for supplying conditioned air under pressureto the inlet ducts.

4. In apparatus of the class described, a kiln and means for producingcross-ventilation thereof, including a plurality of air inlets and aplurality of air outlets substantially symmetrically arrangedtransversely of the kiln, said inlet ducts opening downwardly.

5. In apparatus of the class described, a kiln and means for producingcross-ventilation thereof, including a plurality ofair inletsand aplurality of air outlets disposed at intervals along opposite sides ofthe kiln and near the floor, said inlets and outlets being substantiallysymmetrically arranged transversely of the kiln, and means for supplyingair under pressure to the air inlets.

CHARLES H. CURRIER.

